FreeBSD Security Advisory FreeBSD-SA-01:36.samba

From: FreeBSD Security Advisories (security-advisoriesat_private)
Date: Mon Apr 23 2001 - 20:22:44 PDT

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    FreeBSD-SA-01:36                                           Security Advisory
                                                                    FreeBSD, Inc.
    
    Topic:          samba ports contain locally exploitable /tmp races
    
    Category:       ports
    Module:         samba
    Announced:      2001-04-23
    Credits:        Marcus Meissner <Marcus.Meissnerat_private>
    Affects:        Ports collection prior to the correction date.
    Corrected:      2001-04-18
    Vendor status:  Updated version released
    FreeBSD only:   No
    
    I.   Background
    
    Samba is an implementation of the Server Message Block (SMB)
    protocol.
    
    II.  Problem Description
    
    The samba ports, versions prior to samba-2.0.8 and samba-devel-2.2.0,
    contain /tmp races that may allow local users to cause arbitrary
    files and devices to be overwritten.  Due to easily predictable
    printer queue cache file names, local users may create symbolic links
    to any file or device causing it to be corrupted when a remote user
    accesses a printer.  In addition, the file will be left with world-
    writable permission allowing any user to enter their own data.
    
    The samba ports are not installed by default, nor are they "part of
    FreeBSD" as such: they are part of the FreeBSD ports collection, which
    contains over 5000 third-party applications in a ready-to-install
    format.  The ports collections shipped with FreeBSD 3.5.1 and 4.2
    contain this problem since it was discovered after the releases.
    The ports collection that shipped with FreeBSD 4.3 is not vulnerable
    since this problem was corrected prior to the release.
    
    FreeBSD makes no claim about the security of these third-party
    applications, although an effort is underway to provide a security
    audit of the most security-critical ports.
    
    III. Impact
    
    Unprivileged local users may cause arbitrary files or devices to be
    corrupted and gain increased privileges on the local system.
    
    If you have not chosen to install the samba ports/packages, then
    your system is not vulnerable to this problem.
    
    Samba servers that do not have any printers configured are not
    vulnerable.
    
    IV.  Workaround
    
    Deinstall the samba port/package, if you have installed it.
    
    V.   Solution
    
    One of the following:
    
    1) Upgrade your entire ports collection and rebuild the samba port.
    
    2) Deinstall the old package and install a new package dated after the
    correction date, obtained from:
    
    [i386]
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/net/samba-2.0.8.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/net/samba-2.0.8.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/net/samba-devel-2.2.0.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/net/samba-devel-2.2.0.tgz
    
    NOTE: it may be several days before updated packages are available.
    
    [alpha]
    Packages are not automatically generated for the alpha architecture at
    this time due to lack of build resources.
    
    3) download a new port skeleton for the samba from:
    
    http://www.freebsd.org/ports/
    
    and use it to rebuild the port.
    
    4) Use the portcheckout utility to automate option (3) above. The
    portcheckout port is available in /usr/ports/devel/portcheckout or the
    package can be obtained from:
    
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz
    
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